1. Field of the Invention
In a driving apparatus that drives a sensor, a heater and an actuator used for controlling power trains such as an engine or a change gear of automobiles, this invention is related to the driving apparatus with a function for detecting an electric current at the time of driving or a trouble diagnosis, and to a method for detecting its electric current.
2. Description of the Prior Art
In the prior art, at the time of driving or a trouble diagnosis of elements such as a sensor, a heater and an actuator used for controlling power trains such as an engine or a change gear of automobiles, driving apparatuses that drive each of the elements and devices for detecting the electric current that flows through each of the driving apparatuses were provided. The quantity of an electric current to operate a heater or an actuator was larger than that of another electric current to operate a sensor, therefore, it was necessary to reduce the electric current capacity of an electric current detecting device for detecting the electric current for a sensor and to increase the electric current capacity for a heater and an actuator. This operation is disclosed in Japanese utility model patent publication No. 6-39071, for example.
In the above prior art, the driving apparatus and the electric current detector are provided to every element, therefore, the number of driving apparatuses and electric current detectors are the same as the number of elements, consequently the enlargement of the whole driving apparatus becomes a problem. In addition, as the above elements were installed in a dispersed manner in many places of an automobile, a harness joining an element with a driving apparatus or with the electric current detecting devices or a harness linking between the electric current detecting devices and processing equipment for processing signals from the electric current detecting devices became complicated. Consequently, there was a problem that the electric circuit of the driving apparatus became complicated.